What are the two testing criteria for production water under the Produce Safety Rule?

• A. 126 or less CFU generic E. coli per 100 mL water geometric mean and 410 or less CFU generic E. coli per 100 mL water STV
• B. 100 or less CFU per 100 mL and 300 or less CFU per 100 mL
• C. 150 or less CFU per 100 mL and 450 or less CFU per 100 mL
• D. 200 or less CFU per 100 mL and 500 or less CFU per 100 mL

Answer: (A)

Two testing criteria govern production water quality under the Produce Safety Rule: the geometric mean and the statistical threshold value (STV) for generic E. coli per 100 mL. The geometric mean looks at several water samples together and provides a central tendency that dampens the effect of any single high result, ensuring the overall water quality is consistently low. The target geometric mean is 126 CFU per 100 mL. The STV, on the other hand, accounts for variability across the sample set and protects against occasional spikes; the STV limit is 410 CFU per 100 mL. Together, these criteria ensure both a low average contamination level and control over variability. If water doesn’t meet either criterion, corrective actions are required, such as treating the water or stopping its use for producing edible produce until it complies. The other numerical pairings do not match the Produce Safety Rule standards.